Challita Caren, Dahdouh Elias, Attieh Michel, Dandachi Iman, Ragheb Elio, Taoutel Roy, Tanba Carl, Daoud Ziad
Faculty of Medicine, Clinical Microbiology Lab, University of Balamand, Lebanon.
Faculty of Veterinary, Department of Animal Health, Universidad Complutense de Madrid, Madrid, Spain.
J Infect Public Health. 2017 Sep-Oct;10(5):572-578. doi: 10.1016/j.jiph.2016.11.004. Epub 2017 Feb 16.
Muti-Drug Resistant Organisms (MDROs) are problematic all over the world, especially in Lebanon. High fecal carriage rates of MDR Enterobacteriaceae were reported from Lebanese nursing homes. Some studies show that MDROs have a fitness cost as compared to sensitive isolates. In this study, the competitive growth of MDR Escherichia coli obtained from fecal samples from elderly is assessed. Fecal swabs from ten elderly patients from a Lebanese nursing home were obtained between June and December, 2015. Isolates were identified by API 20E and antimicrobial susceptibilities were determined. Production of ESBL (extended spectrum β lactamase), MBL (metallo β lactamse), AmpC and KPC (Klebsiella pneumonia carbapenemase) was detected phenotypically by the use of EDTA, PBA, cloxacillin, and DDSTs. In-vitro competition assays were performed using E. coli isolates with different combinations of bacterial resistance. A total of 117 isolates was obtained with 71.8% E. coli, 7.7% of which were ESBL and 5.1% AmpC producers. Sensitive E. coli isolates out-competed all other isolates when in competition, followed sequentially by ESBL, AmpC, and OXA-48 (oxacillin) producers. This study shows an advantage of sensitive E. coli strains obtained from fecal samples to out-compete resistant strains in specific in-vitro conditions. This ability could be exploited in the elimination of MDR organisms from the gut flora, after further investigation.
多重耐药菌（MDROs）在全球范围内都是一个难题，在黎巴嫩尤为突出。据报道，黎巴嫩疗养院中多重耐药肠杆菌科细菌的粪便携带率很高。一些研究表明，与敏感菌株相比，多重耐药菌存在适应性代价。在本研究中，评估了从老年人粪便样本中分离出的多重耐药大肠杆菌的竞争性生长情况。2015年6月至12月期间，从黎巴嫩一家疗养院的10名老年患者中采集了粪便拭子。通过API 20E鉴定分离株，并测定其抗菌药敏性。通过使用EDTA、PBA、氯唑西林和双碟协同试验（DDSTs），表型检测超广谱β-内酰胺酶（ESBL）、金属β-内酰胺酶（MBL）、AmpC和肺炎克雷伯菌碳青霉烯酶（KPC）的产生情况。使用具有不同细菌耐药组合的大肠杆菌分离株进行体外竞争试验。共获得117株分离株，其中71.8%为大肠杆菌，其中7.7%为ESBL生产者，5.1%为AmpC生产者。在竞争中，敏感大肠杆菌分离株比所有其他分离株更具竞争力，其次依次是ESBL、AmpC和OXA-48（苯唑西林）生产者。本研究表明，从粪便样本中获得的敏感大肠杆菌菌株在特定体外条件下比耐药菌株更具竞争优势。经过进一步研究后，这种能力可用于从肠道菌群中消除多重耐药菌。
